This invention relates to convolving or cross-correlating segments of time-varying information.
In order to compare different information segments (for example, a time-dependent reference signal used in radar and a time-dependent echo signal received back from a distant object), it may be useful to convolve or cross-correlate the segments.
The convolution or cross-correlation can be performed by a digital computer if the time-varying information segments are already in the form of (or have been converted into) a succession of digital values.
In another technique, the segments can be converted to acoustic waves and propagated through a transparent solid; light scattered from the solid is then detected as a representation of the convolution or cross-correlation. The temporal response of such a system (and hence its processing rate) is governed by a number of factors including the frequency and propagation speed of the acoustic waves in the transparent solid.